In orthopedic work, broken bones, sprains and other injuries often must be immobilized to obtain suitable healing. Immobilization is ordinarily achieved through the application of a cast on the patient. Two kinds of casts will be described and they differ only in the location on the body of the patient. The first kind is the typical cast installed for a broken limb. Such a cast is constructed in situ placing a type of elastic sleeve on the body of the patient. If, for instance the forearm is broken, the elastic sleeve will typically extend from near the hand up toward the elbow and past as necessary. The elastic sleeve is the material immediately adjacent to the skin and of course, it is placed there to serve as a base for the cast. The cast itself is then shaped around the elastic sleeve which becomes an integral part thereof.
Heretofore, the second layer formed has been several wraps, typically in the range of two to six wraps, of a felted cloth. The soft felting material serves as a cushion and is nonrigid to thereby define a soft media with some give. Multiple wraps of the soft material are placed around the area to be enclosed in the cast. The third material which comprises the cast is a type of plaster bandage. It is a supplied in a continuous spool to be wrapped around the cast area. It is first dipped in water and the water reacts with the plaster bandage to form what is eventually a bandage reinforced plaster cast. Of course, the cast must cure in the typical cure time is in the range of 48 to 72 hours after application. The cure time depends on the number of wraps of the plaster bandage. Representative materials for the fabrication of the cast are supplied by Johnson and Johnson and the three materials are sold under the following respective trademarks:
Stockinette, Sof-rol, and Specialist.
Another type of cast is what might be termed a body cast which might be placed on a person with a broken pelvis, hip, spine or the like. A body cast will have parts corresponding to the three basic constituents named above although they may be supplied in different forms.
Innumerable problems have arisen with plaster casts. First of all, there is the lengthy cure interval. While some breaks are quite painful and significantly incapacitate the patient, often a break will not be so painful and the patient becomes quickly restless during the cure period. This is a particularly difficult problem with small children. They want to get up and move around before the cast has become hard. If they do move around, they may in fact distort or mishape the cast during movement and by so doing reduce the amount of support which the cast furnishes to the break or sprain.
Even though the cast may in fact be cured without distortion during the curing process, they are often subsequently damaged. For instance, they are susceptible to absorbtion of water from either perspiration, humid environments, or other sources. When water impinges on a cast from any of the sources mentioned above, it is absorbed into the plaster cast and weakens the cast. The cast will be weakened, for instance, if the cast is placed on the leg of a patient who subsequently walks in the rain or at a time when there is dew on the ground. The patient may in fact perspire quite freely inside the cast or in attempting to bath, splash a substantial amount of water on the cast. In either case, the water weakens the cast which increases the chance of breakage or distortion after which the cast does not lend the required support to the patient. This manifests itself in poorly set bones or when observed in timely fashion, often requires replacement with a substitute cast.
It is with these problems in mind that the present invention has been devised. It is an apparatus and method which is adapted to be incorporated in a cast. It dries the interior of the cast and particularly that portion of the cast adjacent to the skin. This protects the skin of the patient and moreover, strengthens the cast itself. It enables the cast to dry or cure, thereby achieving a rigid structure and it further keeps it dry and therefore rigid. This particularly is advantageous in casts exposed to substantial amounts of water such as a walking cast placed on the foot and lower leg. It improves the strength of the cast also.